The present invention relates to photonics chips and, more specifically, to structures that include a waveguide and methods of fabricating a structure that includes a waveguide.
Photonics chips are used in many applications and systems including, but not limited to, data communication systems and data computation systems. A photonics chip integrates optical components, such as waveguides and bends, and electronic components, such as field-effect transistors, into a unified platform. Among other factors, layout area, cost, and operational overhead may be reduced by the integration of both types of components.
The optical components of a photonics chip may be fabricated by patterning a layer composed of silicon nitride. The optical components are formed over a dielectric layer stack that includes a layer of silicon nitride defining a continuous and unbroken slab over the optical components. Because of the manner in which it is deposited, the silicon nitride in this slab incorporates hydrogen that, through nitrogen-hydrogen bonds, causes absorption of the optical signals propagating in the optical components. An unwanted consequence of the absorption is optical loss, which may be undesirable for long-range routing of the propagating optical signals in the optical components of the photonics chip.
Improved structures that include a waveguide and methods of fabricating a structure that includes a waveguide are needed.